Two studies link blood pressure, brain health

Published on Thursday, August 22, 2019

By: Karen Bascom

A pair of articles published in the August 13 issue of Journal of the American Medical Association show that controlling high blood pressure early and aggressively can have positive effects on brain health later in life.

University of Mississippi Medical Center physicians and scientists had significant roles in developing and conducting the two landmark studies that produced the papers. The Atherosclerosis Risk in Communities (ARIC) Study has spent more than 30 years studying risks factors for cardiovascular disease as people age, including hypertension. More recently, the SPRINT trial, short for Systolic blood PRessure INTervention, compared the effects of treating high blood pressure with a target of 120/80 mmHg instead of 140/90 mmHg in older adults at risk for cardiovascular disease.

According to the Centers for Disease Control and Prevention, 75 million American have high blood pressure, which can raise the risk of heart disease and related conditions.

Dr. Tom Mosley and Dr. Gwen Windham, both professors of medicine at UMMC, are two of the authors of the recent ARIC publication. Mosley is the director of the ARIC Study site in Jackson.

“The ARIC study is designed to discover associations between midlife and late-life health,” Mosley said.

In the study, 4761 adults participated in six visits over 30 years where researchers measured blood pressure and cognitive impairment, among other metrics. The scientists defined hypertension as having either systolic BP measurements above 140 mmHg or diastolic BP above 90 mmHg, and hypotension as systolic BP below 90 or diastolic below 60 mmHg. They assessed dementia through cognitive exams, questionnaires, and health records. Overall, about 11 percent of participants developed dementia.

According to the paper, people who had hypertension in both middle and late-life were 49 percent more likely to develop dementia than people with normal-level BP throughout the study.  In addition, people who had hypertension in midlife but hypotension later were 62 percent more likely to develop dementia compared to normotensive participants.

“These most recent findings add to the growing body of evidence that preventing and controlling high blood pressure in midlife is one of the most effective ways to decrease the risk of developing dementia later,” Mosley said.

What level of control is sufficient to decrease the risk of dementia? Recently, the SPRINT trial showed that controlling BP with a target of 120/80 mmHg in mind was associated with lower all-cause mortality. SPRINT MIND, which stands for Memory and Cognition in Decreased Hypertension, investigators wanted to know if this intervention improved brain health as well.

“Dementia is brain failure, and many processes can damage the brain,” said Dr. Alexander Auchus, professor of neurology and one of the authors of the recent SPRINT MIND paper.

After about four years of blood pressure treatment, 449 adults received a brain MRI (magnetic resonance imaging) to look for white matter disease, or the loss of tissues deep in the brain. These changes happen more often in older people and can impair memory, problem solving and balance.

People in the 120/80 group had a smaller increase in white matter lesions in the brain than those in the 140/90 group. However, this relationship was relatively small, which may in part be due to the trial’s early termination.

“This study is important insofar as it shows that strict blood pressure control was associated with less development of damage to the brain's white matter,” Auchus said. “Prevention of brain damage is always desirable compared to managing the consequences of damage after it occurs.”

Some of the best ways to manage your blood pressure:

• If you smoke, quit
• Eat a diet high in vegetables, fruits, whole grains and lean proteins
• Increase physical activity
• Work with your physician for management and treatment options

The National Institutes of Health funds both ARIC and SPRINT.

To learn more about the two studies, watch this video from JAMA.